Engine Noise in VHF

[dkelsey38]

I run a 200 hp Yamaha which produces lots of radio noise. I've tried all kinds of things, but so far nada ... I have tried disconnecting each of the 6 spark coils in turn to see if anyone was malfunctioning. No result. The plugs are all resistor. The noise is coming in on the antenna. If I disconnect the antenna, no noise. Yamaha isn't any help and the local dealer has no suggestions. If anyone has any ideas, I love to hear them. Does anyone know of a noise filter that would work. I tried on the power input, but it didn't help

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[oldsaltoz]

G'day dkelsey38,

I assume you have the radio power supply hooked up direct to the battery,
if not give a try. . . . . .



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[BobWilliamson]

Have you considered that it might be low tention noise???

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[Bergman]

A few thoughts

Most likely noise coming thro power. Try a separate 12v source on radio. Or maybe better still try a hand held in the boat see if that is affected. If this is clear then filtering in power leads and careful checking of earthing arrangements. particularly check for "earth loops" where different items are connected to different earthing points. This can be a major source of noise.

Worth checking on aerial too. connect only the centre conductor to radio and see if noise is present. If check for earth connection on outer screen of co-ax. There probably will be one. If there is consider change of antenna to different type, perhaps ruber duck or 5/8 wave. If not check for connection between inner and outer of coax, if there is none you have an aerial problem.

If none of this works get some small ferrite rings, Maplins have them, put one on every bit of wire connected to engine. Then put 2 or 3 turns of the power feed cables to the VHF on a larger ferrite ring one suitable for VHF and try that.

If none of this works
er well I'm stuck too - either try sailing or post again with results

Good Luck

PS Noise problems are always the most difficult to solve - just to cheer you up


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